Unsaturated polyester resin compositions

ABSTRACT

The present invention relates to a two-component composition comprising a first component and a second component, wherein the first component being a pre-accelerated resin composition comprising an unsaturated polyester resin or vinyl ester resin and a copper 2+  compound, at least one N-containing organic base selected from an amine compound and/or an ammonium salt; and wherein copper is present in an amount of at least 50 ppm (relative to the primary resin system), wherein the resin composition contains less than 0.01 mmol cobalt per kg primary resin system, the resin composition has an acid value in the range of from 0.001-300 mg KOH/g of resin composition, the molecular weight of the resin containing reactive unsaturations is in the range of from 500 to 200,000 g/mole and wherein the second component comprises a peroxide compound.

This application is a continuation of commonly owned copending U.S.patent application Ser. No. 12/307,481, filed Oct. 12, 2009 (nowabandoned) which is the national phase application of InternationalApplication No. PCT/EP2007/005965, filed Jul. 5, 2007, which designatedthe U.S. and claims priority to EP Application No. 06014013.4, filedJul. 6, 2006, the entire contents of each of which are herebyincorporated by reference.

The present invention relates to a two-component composition comprisinga first component and a second component, wherein the first componentbeing a resin composition comprising an unsaturated polyester resin orvinyl ester resin and the second component comprises a peroxidecompound. The resin compositions show good curing properties in theabsence of cobalt. The resin compositions also show slight gel-timedrift tendency. The present invention further also relates to objectsand structural parts prepared from such two component compositions. Thepresent invention finally also relates to methods for radically curingsuch two-component compositions.

As used herein, the term “two-component system” refers to systems wheretwo separate components (A and B) are being spatially separated fromeach other, for instance in separate cartridges or the like, and isintended to include any system wherein each of such two separatecomponents (A and B) may contain further separate components. Thecomponents are combined at the time the system is used.

As meant herein, objects and structural parts are considered to have athickness of at least 0.5 mm and appropriate mechanical properties. Theterm “objects and structural parts” as meant herein also includes curedresin compositions as are used in the field of chemical anchoring,construction, roofing, flooring, windmill blades, containers, tanks,pipes, automotive parts, boats, etc.

As meant herein the term gel-time drift (for a specifically selectedperiod of time, for instance 30 or 60 days) reflects the phenomenon,that—when curing is performed at another point of time than at thereference standard moment for curing, for instance 24 hours afterpreparation of the resin—the gel time observed is different from that atthe point of reference. For unsaturated polyester resins, as cangenerally be cured under the influence of peroxides, gel time representsthe time lapsed in the curing phase of the resin to increase intemperature from 25° C. to 35° C. Normally this corresponds to the timethe fluidity (or viscosity) of the resin is still in a range where theresin can be handled easily. In closed mould operations, for instance,this time period is very important to be known. The lower the gel-timedrift is, the better predictable the behavior of the resin (and theresulting properties of the cured material) will be.

W. D. Cook et al. in Polym. Int. Vol. 50, 2001, at pages 129-134describe in an interesting article various aspects of control of geltime and exotherm behavior during cure of unsaturated polyester resins.They also demonstrate how the exotherm behavior during cure of suchresins can be followed. FIGS. 2 and 3 of this article show the gel timesin the bottom parts of the exotherms measured. Because these authorsfocus on the exotherms as a whole, they also introduced some correctionof the exotherms for heat loss. As can be seen from the figures,however, such correction for heat loss is not relevant for gel timesbelow 100 minutes.

Gel time drift (hereinafter: “Gtd”) can be expressed in a formula asfollows:

Gtd=(T _(25->35° C. at y-days) −T _(25-35° C. after mixing))/T_(25->35° C. after mixing)×100%   (formula 1)

In this formula T_(25->35° C.) (which also might be represented byT_(gel)) represents, as mentioned above, the time lapsed in the curingphase of the resin to increase in temperature from 25° C. to 35° C. Theadditional reference to “at y days” shows after how many days ofpreparing the resin the curing is effected.

All polyester resins, by their nature, undergo some changes over timefrom their production till their actual curing. One of thecharacteristics where such changes become visible is the gel-time drift.The state of the art unsaturated polyester resin systems generally arebeing cured by means of initiation systems. In general, such unsaturatedpolyester resin systems are cured under the influence of peroxides andare accelerated (often even pre-accelerated) by the presence of metalcompounds, especially cobalt salts, as accelerators. Cobalt naphthenateand cobalt octanoate are the most widely used accelerators. In additionto accelerators, the polyester resins usually also contain inhibitorsfor ensuring that the resin systems do not gellify prematurely (i.e.that they have a good storage stability). Furthermore, inhibitors arebeing used to ensure that the resin systems have an appropriate gel timeand/or for adjusting the gel-time value of the resin system to an evenmore suitable value.

Most commonly, in the state of the art, polymerization initiation ofunsaturated polyester resins, etc. by redox reactions involvingperoxides, is accelerated or pre-accelerated by a cobalt compound incombination with another accelerator.

An excellent review article of M. Malik et al. in J.M.S.—Rev Macromol.Chem. Phys., C40(2 & 3), p. 139-165 (2000) gives a good overview of thecurrent status of resin systems. Curing is addressed in chapter 9. Fordiscussion of control of gel time reference can be made to the articleof Cook et al. as has been mentioned above. Said article, however, doesnot present any hint as to the problems of gel-time drift as are beingsolved according to the present invention.

The phenomenon of gel-time drift, indeed, so far got quite littleattention in the literature. Most attention so far has been given inliterature to aspects of acceleration of gel time in general, and toimproving of pot-life or shelf life of resins. The latter aspects,however, are not necessarily correlated to aspects of gel-time drift,and so, the literature until now gives very little suggestions as topossible solutions for improvement of (i.e. lowering of) gel-time drift.

Accordingly, for the unsaturated polyester resins and vinyl ester resinsas are part of the current state of the art there is still need forfinding resin systems showing reduced gel-time drift tendency, or inother words, resin systems having only slight gel-time drift when curedwith a peroxide. Preferably the mechanical properties of the resincomposition after curing with a peroxide are unaffected (or improved) asa result of the changes in the resin composition for achieving thereduced gel-time drift. Moreover, for environmental reasons, thepresence of cobalt in the resins is less preferred.

The present inventors now, surprisingly, found that two-componentcompositions with good curing properties could be obtained by providinga two-component composition comprising a first component and a secondcomponent, wherein the first component being a pre-accelerated resincomposition comprising an unsaturated polyester resin or vinyl esterresin and

-   -   a. a copper²⁺ compound,    -   b. at least one N-containing organic base selected from an amine        compound and/or an ammonium salt; wherein the amine compound        having the following formula:

and the ammonium salt having the following formula R¹R²R³N⁺H whereby R¹,R² and R³ each individually may represent hydrogen (H), C₁-C₂₀ alkyl,C₅-C₂₀ cycloalkyl or C₇-C₂₀ alkylaryl, that each optionally may containone or more hetero-atoms (e.g. oxygen, phosphor or sulphur atoms) and/orsubstituents and a ring may be present between R₁ and R₂, R₂ and R₃and/or R₁ and R₃, which may contain heteroatoms and wherein copper ispresent in an amount of at least 50 ppm (relative to the primary resinsystem), wherein the resin composition contains less than 0.01 mmolcobalt per kg primary resin system, the resin composition has an acidvalue in the range of from 0.001-300 mg KOH/g of resin composition, themolecular weight of the resin containing reactive unsaturations is inthe range of from 500 to 200,000 g/mole; and wherein the secondcomponent comprises a peroxide compound.

The resin composition of the two-component composition according to thepresent invention being free of blowing agents.

According to the present invention, compositions having good curingproperties can be obtained, i.e. the compositions according to theinvention have short gel time, short peak time and/or high peaktemperature. In the curing of unsaturated polyester resins or vinylesters, gel time is a very important characteristic of the curingproperties. In addition also the time from reaching the gel time toreaching peak temperature, and the level of the peak temperature (higherpeak temperature generally results in better curing) are important. Inaddition, the compositions according to the present invention can beobtained with reduced gel-time drift tendency.

Furthermore the inventors have surprisingly found that besides the goodcuring properties also cured objects with low amounts of residualstyrene and residual benzaldehyde can be obtained.

As used herein, the acid value of the resin composition is determinedtitrimetrically according to ISO 2114-2000. As used herein, themolecular weight of the resin is determined using gel permeationchromatography according to ISO 13885-1.

U.S. Pat. No. 4,524,177 discloses that copper compounds in an amountsfrom 0.0005 to 0.2% by weight, preferably from 0.001 to 0.05% by weight,based on the ethylenically unsaturated compound to be polymerized, canbe used for basic stabilization of the ethylenically unsaturatedcompounds to be polymerized. Thus, this document teaches that copper isan inhibitor. Similar, GB834286 teaches that small amounts of a solubleform of copper in the range 0.25 ppm to 10 ppm of copper improves theinhibiting properties of inter alias aromatic amines, quaternaryammonium salts and amine salts. U.S. Pat. No. 6,329,475 furthermoreteaches that an amine acts as an inhibitor for catalyst compositioncontaining copper. Thus, there appears no indication in these prior artthat acceleration can be achieved with a N-containing organic baseselected from an amine compound and/or an ammonium salt and copper.However, WO-A-9012824 discloses an accelerator composition for thecuring of unsaturated polyester resins comprising a complex of certainmetal salts with organic nitrogen compounds. Preferably, the metal isselected from copper, vanadium, lithium, nickel, iron, magnesium andcobalt. For copper, an amount of from 0.1 to 10 ppm is mentioned.Furthermore, according to this document, higher amounts of copper do notfurther contribute to the activity. It has however been found that suchlow amounts of copper does not result in efficient curing, whereas theuse of copper in an amount of at least 50 ppm in combination with aN-containing organic base can result in efficient curing.

The unsaturated polyester resin or vinyl ester resin as is comprised inthe compositions according to the present invention, may suitably beselected from the unsaturated polyester resins or vinyl ester resin asare known to the skilled man. Examples of suitable unsaturated polyesteror vinyl ester resins to be used as basic resin systems in the resins ofthe present invention are, subdivided in the categories as classified byMalik et al., cited above.

-   -   (1) Ortho-resins: these are based on phthalic anhydride, maleic        anhydride, or fumaric acid and glycols, such as 1,2-propylene        glycol, ethylene glycol, diethylene glycol, triethylene glycol,        1,3-propylene glycol, dipropylene glycol, tripropylene glycol,        neopentyl glycol or hydrogenated bisphenol-A. Commonly the ones        derived from 1,2-propylene glycol are used in combination with a        reactive diluent such as styrene.    -   (2) Iso-resins: these are prepared from isophthalic acid, maleic        anhydride or fumaric acid, and glycols. These resins may contain        higher proportions of reactive diluent than the ortho resins.    -   (3) Bisphenol-A-fumarates: these are based on ethoxylated        bisphenol-A and fumaric acid.    -   (4) Chlorendics: are resins prepared from chlorine/bromine        containing anhydrides or phenols in the preparation of the UP        resins.    -   (5) Vinyl ester resins: these are resins, which are mostly used        because of their because of their hydrolytic resistance and        excellent mechanical properties, as well as for their low        styrene emission, are having unsaturated sites only in the        terminal position, introduced by reaction of epoxy resins (e.g.        diglycidyl ether of bisphenol-A, epoxies of the phenol-novolac        type, or epoxies based on tetrabromobisphenol-A) with        (meth)acrylic acid. Instead of (meth)acrylic acid also        (meth)acrylamide may be used.

Besides these classes of resins also so-called dicyclopentadiene (DCPD)resins can be distinguished as unsaturated polyesters. As used herein, avinyl ester resin is a (meth)acrylate functional resin. Besides thevinyl ester resins as described in Malik et al., also the class of vinylester urethane resins (also referred to urethane methacylate resins) canbe distinguished as vinyl ester resins. Preferably, the vinyl ester usedin the present invention is a resin obtained by the esterification of anepoxy resin with (meth)acrylic acid or (meth)acrylamide.

All of these resins, as can suitably used in the context of the presentinvention, may be modified according to methods known to the skilledman, e.g. for achieving lower acid number, hydroxyl number or anhydridenumber, or for becoming more flexible due to insertion of flexible unitsin the backbone, etc. The class of DCPD-resins is obtained either bymodification of any of the above resin types by Diels-Alder reactionwith cyclopentadiene, or they are obtained alternatively by firstreacting maleic acid with dicyclopentadiene, followed by the resinmanufacture as shown above.

Of course, also other reactive groups curable by reaction with peroxidesmay be present in the resins, for instance reactive groups derived fromitaconic acid, citraconic acid and allylic groups, etc. Accordingly, theunsaturated polyester resins or vinyl ester resins used in the presentinvention may contain solvents. The solvents may be inert to the resinsystem or may be reactive therewith during the curing step. Reactivesolvents are particularly preferred. Examples of suitable reactivesolvents are styrene, α-methylstyrene, (meth)acrylates,N-vinylpyrrolidone and N-vinylcaprolactam.

The unsaturated polyester resins and vinyl ester resins as are beingused in the context of the present invention may be any type of suchresins, but preferably are chosen from the group of DCPD-resins,iso-phthalic resins and ortho-phthalic resins and vinyl ester resins.More detailed examples of resins belonging to such groups of resins havebeen shown in the foregoing part of the specification. More preferably,the resin is an unsaturated polyester resin preferably chosen from thegroup of DCPD-resins, iso-phthalic resins and ortho-phthalic resins.

The resin composition of the two-component composition according to thepresent invention generally contains less than 5 wt. % water.

The resin composition contains less than 0.01 mmol cobalt per kg primaryresin system. Preferably, the resin composition contains less than 0.001mmol Co per kg primary resin system. Most preferably the resincomposition is free of cobalt.

According to the invention, the copper²⁺ compound present in the resincomposition is preferably a copper salt or complex. Even morepreferably, the copper compound is a copper²⁺ salt. In view of thesolubility of the copper compound in the resin composition, the coppercompound is preferably an organo soluble copper compound like forinstance copper carboxylates, copper acetoacetates and copper chlorides.It will be clear that, instead of a single copper compound also amixture of copper compounds can be used.

The copper is present in the resin composition in an amount of at least50 ppm (relative to the primary resin system) (0.8 mmol Cu per kg ofprimary resin system), preferably in an amount of at least 100 ppm Cu.The upper limit of the copper content is not very critical, although forreasons of cost efficiency of course no extremely high concentrationswill be applied. Generally the concentration of the copper compound inthe primary resin system will be such that the copper is present in anamount lower than 1000 ppm Cu (relative to the primary resin system) (16mmol Cu per kg of primary resin system), preferably lower than 500 ppmCu.

For understanding of the invention, and for proper assessment of theamounts of copper compound to be present in the resin composition, theterm “primary resin system” as used herein is understood to mean thetotal weight of the resin, but excluding any fillers as may be used whenapplying the resin system for its intended uses. The primary resinsystem therefore consists of the unsaturated polyester resin or vinylester resin, any additives present therein (except for the peroxidecomponent that is to be added shortly before the curing) soluble in theresin, such as accelerators, promoters, inhibitors, low-profile agents,colorants (dyes), thixotropic agents, release agents etc., as well asstyrene and/or other solvents as may usually be present therein. Theamount of additives soluble in the resin usually may be as from 1 to 25wt. % of the primary resin system; the amount of styrene and/or othersolvent may be as large as up to 50 wt. % of the primary resin system.The primary resin system, however, explicitly does not include compoundsnot being soluble therein, such as fillers (e.g. glass or carbonfibers), talc, clay, solid pigments (such as, for instance, titaniumdioxide (titanium white)), flame retardants, e.g. aluminum oxidehydrates, etc.

The N-containing organic base of the resin composition is an aminecompound having the following formula:

or is an ammonium salt having the following formula R¹R²R³N⁺H wherebyR¹, R² and R³ each individually may represent hydrogen (H), C₁-C₂₀alkyl, C₅-C₂₀ cycloalkyl or C₇-C₂₀ alkylaryl, that each optionally maycontain one or more hetero-atoms (e.g. oxygen, phosphor or sulphuratoms) and/or substituents and a ring may be present between R₁ and R₂,R₂ and R₃ and/or R₁ and R₃, which may contain heteroatoms. In apreferred embodiment, R¹, R² and R³each individually may representhydrogen (H), C₁-C₂₀ alkyl or C₇-C₂₀ alkylaryl, that each optionally maycontain one or more hetero-atoms (e.g. oxygen, phosphor or sulphuratoms) and/or substituents

In a preferred embodiment, R¹, R² and R³are hydrogen. In anotherpreferred embodiment, R¹, R² and R³ each individually may represent aC₁-C₂₀ alkyl. In yet another preferred embodiment, at least one of R¹,R² and R³ is an alkyl-O—R⁴ group, whereby R⁴ is hydrogen, a C₁-C₂₀ alkylgroup or a ring is present between R⁴ and at least one of the other Rgroups. In this preferred embodiment, the —O—R⁴ group is preferably inthe R-position with respect to the nitrogen atom.

Preferably, the amount of the N-containing organic base is from 0.05 to5% by weight, calculated on the total weight of the primary resinsystem. More preferably, the amount of the N-containing organic base isfrom 0.1 to 2% by weight; even more preferably between 0.25 and 1% byweight.

In the resin composition, the molar ratio between the copper and thebasic functionality of the base is preferably from 40:1 to 1:125, morepreferably from 8:1 to 1:25.

The peroxide compound present in the second component of thetwo-component composition according to the present invention is used forthe initiation of curing the resin and can be any peroxide known to theskilled man for being used in curing of unsaturated polyester resins orvinyl ester resins. Such peroxides include organic and inorganicperoxides, whether solid or liquid; also hydrogen peroxide may beapplied. Examples of suitable peroxides are, for instance, peroxycarbonates (of the formula —OC(O)O—), peroxyesters (of the formula—C(O)OO—), diacylperoxides (of the formula —C(O)OOC(O)—),dialkylperoxides (of the formula —OO—), etc The peroxides can also beoligomeric or polymeric in nature. An extensive series of examples ofsuitable peroxides can be found, for instance, in US 2002/0091214-A1,paragraph [0018]. The skilled man can easily obtain information aboutthe peroxides and the precautions to be taken in handling the peroxidesin the instructions as given by the peroxide producers.

Preferably, the peroxide is chosen from the group of organic peroxides.Examples of suitable organic peroxides are: tertiary alkylhydroperoxides (such as, for instance, t-butyl hydroperoxide), otherhydroperoxides (such as, for instance, cumene hydroperoxide), thespecial class of hydroperoxides formed by the group of ketone peroxides(perketones, being an addition product of hydrogen peroxide and aketone, such as, for instance, methyl ethyl ketone peroxide andacetylacetone peroxide), peroxyesters or peracids (such as, forinstance, t-butyl peresters, benzoyl peroxide, peracetates andperbenzoates, lauryl peroxide, including (di)peroxyesters), -perethers(such as, for instance, peroxy diethyl ether). Often the organicperoxides used as curing agent are tertiary peresters-or tertiaryhydroperoxides, i.e. peroxy compounds having tertiary carbon atomsdirectly united to an —O-acyl or —OOH group. Clearly also mixtures ofthese peroxides with other peroxides may be used in the context of thepresent invention. The peroxides may also be mixed peroxides, i.e.peroxides containing any two of different peroxygen-bearing moieties inone molecule). In case a solid peroxide is being used for the curing,the peroxide is preferably benzoyl peroxide (BPO). In case the peroxideis a peranhydride, the resin composition preferably does not contain atertiary aromatic amine.

Most preferably, however, the peroxide is a liquid hydroperoxide. Theliquid hydroperoxide, of course, also may be a mixture ofhydroperoxides. Handling of liquid hydroperoxides when curing the resinsfor their final use is generally easier: they have better mixingproperties and dissolve more quickly in the resin to be cured.

In particular it is preferred that the peroxide is selected from thegroup of ketone peroxides, a special class of hydroperoxides. Theperoxide being most preferred in terms of handling properties andeconomics is methyl ethyl ketone peroxide (MEK peroxide).

In a preferred embodiment of the invention, the resin composition alsocontains one or more reactive diluents. Preferably the amount ofreactive diluents is at least 5 weight %.

Such reactive diluents are especially relevant for reducing theviscosity of the resin in order to improve the resin handlingproperties, particularly for being used in techniques like vacuuminjection, etc. However, the amount of such reactive diluents in theresin composition according to the invention is not critical.Preferably, the reactive diluent is a methacrylate and/or styrene.

In a further preferred embodiment of the present invention, the resincomposition also contains one or more radical inhibitors. Morepreferably, the resin compositions according to the invention containone or more radical inhibitors preferably chosen from the group ofphenolic compounds, stable radicals like galvinoxyl and N-oxyl basedcompounds, catechols and/or phenothiazines.

The amount of radical inhibitor as used in the context of the presentinvention, may, however, vary within rather wide ranges, and may bechosen as a first indication of the gel time as is desired to beachieved. Preferably, the amount of phenolic inhibitor is from about0.001 to 35 mmol per kg of primary resin system, and more preferably itamounts to more than 0.01, most preferably more than 0.1 mmol per kg ofprimary resin system. The skilled man quite easily can assess, independence of the type of inhibitor selected, which amount thereof leadsto good results according to the invention.

Suitable examples of radical inhibitors that can be used in the resincompositions according to the invention are, for instance,2-methoxyphenol, 4-methoxyphenol, 2,6-di-t-butyl-4-methylphenol,2,6-di-t-butylphenol, 2,4,6-trimethylphenol,2,4,6-tris-dimethylaminomethyl phenol,4,4′-thio-bis(3-methyl-6-t-butylphenol), 4,4′-isopropylidene diphenol,2,4-di-t-butylphenol, 6,6′-di-t-butyl-2,2′-methylene di-p-cresol,hydroquinone, 2-methylhydroquinone, 2-t-butylhydroquinone,2,5-di-t-butylhydroquinone, 2,6-di-t-butylhydroquinone,2,6-dimethylhydroquinone, 2,3,5-trimethylhydroquinone, catechol,4-t-butylcatechol, 4,6-di-t-butylcatechol, benzoquinone,2,3,5,6-tetrachloro-1,4-benzoquinone, methylbenzoquinone,2,6-dimethylbenzoquinone, napthoquinone,1-oxyl-2,2,6,6-tetramethylpiperidine,1-oxyl-2,2,6,6-tetramethylpiperidine-4-ol (a compound also referred toas TEMPOL), 1-oxyl-2,2,6,6-tetramethylpiperidine-4-one (a compound alsoreferred to as TEMPON), 1-oxyl-2,2,6,6-tetramethyl-4-carboxyl-piperidine(a compound also referred to as 4-carboxy-TEMPO),1-oxyl-2,2,5,5-tetramethylpyrrolidine,1-oxyl-2,2,5,5-tetramethyl-3-carboxylpyrrolidine (also called3-carboxy-PROXYL), aluminium-N-nitrosophenyl hydroxylamine,diethylhydroxylamine, phenothiazine and/or derivatives or combinationsof any of these compounds.

Advantageously, the amount of radical inhibitor in the resin compositionaccording to the invention is in the range of from 0.0001 to 10% byweight, calculated on the total weight of the primary resin system ofthe resin composition. More preferably, the amount of radical inhibitorin the resin composition is in the range of from 0.001 to 1% by weight.

The two-component composition according to the present invention can beapplied in all applications as are usual for such types of resins. Inparticular they can suitably used in closed mould applications, but theyalso can be applied in open mould applications. For closed mouldapplications it is especially important that the manufacturer of theclosed mould products reliably can use the favorable (i.e. reduced)gel-time drift tendency of the resin compositions according to theinvention. End segments where the unsaturated polyester resin or vinylester resin compositions according to the present invention can beapplied are also marine applications, chemical anchoring, roofing,construction, relining, pipes & tanks, flooring, windmill blades, etc.That is to say, the resin compositions according to the invention can beused in all known uses of unsaturated polyester resins and vinyl esterresins.

The present invention further also relates to a process for radicallycuring a two-component composition according to the invention byeffecting the curing essentially free of cobalt, more preferably in theabsence of cobalt. Essentially free of cobalt means that the cobaltconcentration in the resin composition is less than 0.01 mmol cobalt perkg primary resin system. It has surprisingly been found that thecombination of the copper²⁺ compound in an amount as defined above andthe N containing organic base as defined above accelerates the radicallycuring of the unsaturated polyester or vinyl ester with the peroxide.Preferably, the curing is effected at a temperature in the range of from−20 to +200° C., preferably in the range of from −20 to +100° C., andmost preferably in the range of from −10 to +60° C. (so-called coldcuring).

The present invention further also relates to all such objects orstructural parts as are being obtained when curing the unsaturatedpolyester resin or vinyl ester resin compositions. These objects andstructural parts have excellent mechanical properties. The presentinvention further also relates to a pre-accelerated resin compositionbeing curable with a peroxide compound as described above.

The invention is now demonstrated by means of a series of examples andcomparative examples. All examples are supportive of the scope ofclaims. The invention, however, is not restricted to the specificembodiments as shown in the examples.

EXPERIMENTAL PART

The resins used for curing are commercially available products from DSMComposite Resins B.V., Schaffhausen, Switzerland, and in additionthereto also a resin—hereinafter referred to as Resin A—was specificallyprepared on behalf of the inventors for being used in the tests. Theperoxides used for curing are commercially available products from AkzoNobel Inc.

Preparation of Resin A

184.8 g of propylene glycol (PG), 135.8 g of diethylene glycol (DEG),216.1 g of phthalic anhydride (PAN), 172.8 g of maleic anhydride (MAN),and 0.075 g 2-t-butylhydroquinone were charged in a vessel equipped witha reflux condenser, a temperature measurement device and inert gasinlet. The mixture was heated slowly by usual methods to 205° C. At 205°C. the mixture was kept under reduced pressure until the acid valuereached a value below 16 mg KOH/g resin and the falling ball viscosityat 100° C. was below 50 dPa·s. Then the vacuum was relieved with inertgas, and the mixture was cooled down to 130° C., and thereafter thesolid UP resin so obtained was transferred to a mixture of 355 g ofstyrene and 0.07 g of mono-t-butyl-hydroquinone and was dissolved at atemperature below 80° C. The final resin viscosity reached at 23° C. was640 mPa·s, and the Non Volatile Matter content was 64.5 wt. %.

Monitoring of Curing

In most of the Examples and Comparative Examples presented hereinafterit is mentioned, that curing was monitored by means of standard gel timeequipment. This is intended to mean that both the gel time (T_(gel) orT_(25->35° C.)) and peak time (T_(peak) or T_(25->peak)) were determinedby exotherm measurements according to the method of DIN 16945 whencuring the resin with the peroxides as indicated in the Examples andComparative Examples. The equipment used therefore was a Soform geltimer, with a Peakpro software package and National Instrumentshardware; the waterbath and thermostat used were respectively Haake W26,and Haake DL30.

For some of the Examples and Comparative Examples also the gel-timedrift (Gtd) was calculated. This was done on the basis of the gel timesdetermined at different dates of curing according to formula 1:

Gtd=(T _(25->35° C. at y-days) −T _(25->35° C. after mixing))/T_(25->35° C. after mixing)×100%   (formula 1)

with “y” indicating the number of days after mixing.

EXAMPLES 1a-d AND COMPARATIVE EXPERIMENTS A-J

To a mixture of 90 g resin A, 10 g styrene and 1 g isophorone diaminewas added a copper salt in various amounts and cured with peroxide at25° C. The cure was monitored with the gel time equipment and theresults are shown in table 1.

TABLE 1 peroxide Cure Copper Butanox Trigonox Tgel Tpeak temp Ex Type gppm M-50 (g) C (g) (min) (min) (° C.) comp a CuCl₂ 0.0002 1 1 1 >1200comp b 0.0002 1 2 0 >1200 comp c 0.0021 10 1 1 >1200 comp d 0.0021 10 20 >1200 comp e Cu 0 0 1 1 >1200 comp f naphtenate 0.0012 1 1 1 >1200comp g (8% Cu) 0.0012 1 2 0 >1200 comp h 0.0125 10 2 >1200 comp I 0.012510 1 1 >1200 comp j 0.0125 10 2 0 >1200 1a 0.0625 50 2 0 49.8 67.6 1521b 0.125 100 2 0 20.5 30.2 170 1c 0.25 200 2 0 7.4 13.6 182 1d 0.5 400 20 3.1 8.3 175

These examples and the comparative experiments clearly demonstrate thatusing the low amounts of copper according to WO-A-9012824 no curingtakes place. Only when using the high amounts of copper according to thepresent invention an efficient curing takes place.

EXAMPLES 2a-d

Examples 1a-d were repeated except that 1% Koctanoate in PEG (15%) wasalso added. Curing was performed with 2% (relative to the primary resinsystem) Butanox M-50 and recorded in the gel time equipment. The resultsare shown in the next table.

TABLE 2 Cu (g) Ppm Tgel (min) Tpeak (min) temp (° C.) 2a 0.0625 50 24.533.8 169 2b 0.125 100 7.2 12.7 182 2c 0.25 200 4.7 9.4 181 2d 0.5 400 26.2 178

These results indicate that the cure efficiency using high amounts ofcopper can be further enhanced by the addition of a potassium salt

EXAMPLES 3a-g AND COMPARATIVE EXPERIMENTS K AND L

Formulations were prepared based on 0.25 g Cu naphtenate (200 ppm), 1 gligand, 10 g styrene and 90 g resin A. After stirring for 5 min theformulations were cured using 2 or 3% (relative to the primary resinsystem) Butanox M-50 and monitored using the gel time equipment. Theresults are shown in the next table.

TABLE 3 Tpeak temp Ligand M-50 (%) Tgel (min) (min) (° C.) 3° ammonia 31.1 4 170 3b triethylamine 2 15 26 130 3c dimethylbenzylamine 2 56 79109 3d ethanol amine 3 4.4 8.6 195 3e N-methyl 3 12 19 170 ethanolamine3f N,N-dimethyl ethanol 3 4.2 8.1 179 amine 3g N,N-diethyl ethanol 3 5.610.2 188 amine 3h N,N-dibutyl ethanol 2 9 14 160 amine 3i1-amino-2-propanol 2 19.6 27 162 3j Choline chloride 3 14 31 133 3kmorpholine 3 2.9 7.9 117 3l N-methyl morpholine 3 17.7 34.4 124 3methylene diamine 3 47 78 42 3n tetramethyl ethylen 3 144 187 48 diamineComp k glycol 3 >1200 Comp l dimethyl glycol 3 >1200

These results indicate that most amines are efficient. The mosteffective appear to be ammonia and amines with a R-hydroxy or alkoxygroup.

EXAMPLES 4a-e

Examples 3d, 3f, 3g, 3k and 3l were repeated except that also 0.008 gt-butyl cathecol was added. The cure results are shown in the nexttable.

TABLE 4 Example ligand Tgel (min) Tpeak (min) temp (° C.) 4a ethanolamine 9.3 14.6 191 4b N,N-dimethyl 8.4 12.5 178 ethanol amine 4cN,N-diethyl 8.7 13.4 191 ethanol amine 4d morpholine 4.9 10.3 175 4eN-methyl 28.9 42.2 130 morpholine

These examples together with examples 3d, 3f, 3g, 3k and 3l demonstratethat the curing according to the invention can be tuned using radicalinhibitors

EXAMPLES 5a-l

Formulations were prepared using 100 g of various resin systems, 0.008 gt-butyl catechol, 0.25 g Cu naphtenate solution and 1 gN,N-dimethylethanol amine. Curing was performed using 3% (relative toprimary resin system) Butanox M-50 and monitored using the gel timer theresults are shown in the next table.

TABLE 5 temp resin (g) styrene (g) Tgel (min) Tpeak (min) (° C.) 5a A(90) 10 7.3 11.3 177 5b Palatal P 69-02 (90) 10 25.2 32 165 5c Palatal P4-01 (90) 10 57.1 72 113 5d Palatal P 6-01 (90) 10 18.6 24 153 5e DaronXP-45-A-2 12.7 20 162 5f Synolite 8388-N-1 52.4 71 125

The same experiments, however without t-butyl catechol were repeatedusing morpholine instead of n,n-dimethyl ethanol amine and the resultsare shown below.

TABLE 6 temp resin (g) styrene (g) Tgel (min) Tpeak (min) (° C.) 5g A(90) 10 4 8 176 5h Palatal P 69-02 (90) 10 8 12 179 5i Palatal P 4-01(90) 10 23 33 118 5j Palatal P 6-01 (90) 10 31 38 162 5k Daron-XP-45-A-216 23 145 5l Synolite 8388-N-1 28 39 118

These examples in which various amines were used, illustrate that alltypes of unsaturated resins i.e. unsaturated polyesters, vinyl estersand DCPD resins can be cured according to the invention

EXAMPLE 6

Example 5a was repeated on a 200 g scale. The resin formulation wasdivided into 2 portions of 100 g each. The first portion was cured 5 minafter mixing and the results are similar to above. The second portionwas cured after 84 days resulting in a Tgel=7.2 min, Tpeak=12 min, peaktemp=171° C. The gel time drift of this formulation after 84 days was−1%.

For comparison example 6 was repeated with 0.4 g cobalt naphtenate (10%in spirits) instead of copper naphtenate and dimethyl ethanol amine.This experiment resulted in a gel time drift of 90% after 84 days.

This example illustrates that drift free resins can be obtained usingthe cure system according to the invention.

EXAMPLE 7

Formulations were prepared using 90 g resin A, 10 g styrene, 0.25 g Cunaphtenate solution and 1 g N,N-dimethylethanol amine (examples 7a-7e)respectively 1 g ammonia (30% in water) (examples 7f-7i) respectively 1g ammonium acetate (71% in water) (examples 7j-7k) . Curing wasperformed using 3% (relative to the primary resin system) of variousperoxides and monitored using the gel timer. The results are shown inthe next table.

TABLE 7 Example Tgel (min) Tpeak (min) temp (° C.) 7a Trigonox 21 309327 146 7b Trigonox C 340 357 149 7c Cyclonox LE 50 4.7 7.7 148 7dPerkadox 50L 121 129 117 7e H2O2, 30% in 4 8.4 204 water 7f Butanox M-503 9 184 7g Trigonox 44B 10 15 152 7h Cyclonox LE 50 3 8 170 7i H2O2, 30%in 252 284 123 water 7j Butanox M-50 5 13 176 7k Trigonox 44B 7 12 152

These results indicate that various peroxides can be used. Moreover theyindicate that the type of peroxide can be used to tune the curing. Inaddition, the results indicate that with a proper selection of peroxidewith amine the gel time can be tuned.

EXAMPLE 8

A formulation was prepared from 60 g of a styrene free resin Synolite0513-N-0, 40 g vinyl neodecanoate, 0.175 g Cu naphtenate solution (8%Cu) and 0.9 g N,N-dimethyl ethanol amine. Curing was performed with 2%(relative to the primary resin system) Butanox M-50 resulting in thefollowing cure characteristics: Tgel=5.8 min, Tpeak=11.5 min, Peaktemp=101° C.

This result indicates that styrene free resins can be cured according tothe invention

EXAMPLE 9

A formulation was prepared from 1250 g resin A, 125 g styrene, 2.13 gcopper naphtenate solution (8% Cu) and 18.4 g N,N-dimethyl ethanolamine. After stirring for 5 min. a portion of 100 g was used formeasuring the gel time using 2% (relative to the primary resin system)Butanox M-50: Tgel=10.9 min, T peak =16.1 min and peak temp=157° C.

Separately 360 g of the resin formulation was mixed with 170 glassVetrotex M-123, 450 g/m². To this mixture 7.2 g Butanox M-50 was addedand a laminate was prepared with increasing layer-thickness of 2, 4 and6 plies respectively. After 15 min the laminates reached the gel pointand after 38 min the layer of 6 plies reached a peak temperature of 51°C. Through-cure of the laminates was monitored via the surface hardnessand the results are shown below.

TABLE 8 Hardness (Shore D/Barcol GYZJ 934-1) Time 2 plies 4 plies 6plies 1 hr D60 D65 D75 2 hr D70 10 20 3 hr 5 20 25

These results illustrate that laminates, to be used for constructionpurposes can be obtained with the cure system according to theinvention.

EXAMPLE 10

4 mm castings were prepared based on 500 g resin A according to theformulations described below (all amounts are in grams) and cured withButanox M-50. The 4 mm castings were made between hardened borosilicateglass that was separated with a 4 mm EPDM U-shaped rim The casting werereleased and post cured during 24 hrs at 60° C. and 24 hrs at 80° C.Mechanical properties of the cured objects were determined according toISO 527-2. The Heat Distortion Temperature (HDT) was measured accordingto ISO 75-Ae. Residual styrene contents were measured bygaschromatography using GC-FID (Gas Chromatography with a FlameIonization Detector), using butylbenzene as an internal standard, afterextraction of the cured objects in dichloromethane for 48 hrs.

TABLE 9 10a 10b 10c 10d resin A 500 500 500 500 Cu Naphtenate (8% Cu)0.672 0.672 0.673 0.671 Ammonium acetate (60% in water) 3.40 3.42Ammonia (28-30% in water) 2.31 N,N-dimethyl ethanol amine 4t-butylcatechol 0.025 Butanox M50 5.0 5.0 5.1 4.9 HDT (° C.) 70 73 70 70Tens (MPa) 88 75 90 86 Emod (GPa) 3.7 3.8 3.7 3.6 Elongation at Break(%) 4.4 2.6 4.8 4.6 Rest styrene (%) <0.1 0.06 0.14 0.09 Barcol hardnessGYZJ 934-1 44 44 45 44

These castings results further indicate that the cure system accordingto the invention can be used for construction purposes.

EXAMPLE 11

To 100 grams of Palatal P 4-01 amounts of different bases have beenadded as listed in Table below (all amounts are in grams). Reactivitywas measured and 2- and 4 mm castings were made. The 2 mm castings werecured in an open mould with the top side in contact with air. The 4 mmcastings were made between hardened borosilicate glass that wasseparated with a 4 mm EPDM U-shaped rim. After 24 hrs at 20° C. part ofthe material was post-cured.

Mechanical properties of the cured objects were determined according toISO 527-2. The Heat Distortion Temperature (HDT) was measured accordingto ISO 75-Ae. Residual styrene and benzaldehyde contents were measuredby gaschromatography using GC-FID (Gas Chromatography with a FlameIonization Detector), using butylbenzene as an internal standard, afterextraction of the cured objects in dichloromethane for 48 hrs.

TABLE 10 11a 11b Comp m Comp n Triethanolamine 0.3647 Diethanolamine0.2686 N,N-Diethylacetoacetamide 1 1 1 Coppernaphtenate Cu 8% 0.27 0.270.27 p-tert-butylcatechol (ppm) 200 200 Cobalt-2-ethylhexanoate 1.5 (Co10%) Butanox M-50 2 2 2 2 Gel time (min) 36 19 93.6 6.4 Peak time (min)43.1 24.2 123 19.2 Peakexotherm (° C.) 115 116 90 136 Barcol hardnesscasting 35 35 25 33 2 mm after 7 days Bottomside Barcol hardness casting44 45 35 38 2 mm after 7 days Topside Barcol hardness casting 45 44 4245 4 mm Post cured 16 hrs 40° C. Rest styrene casting 4 mm 0.34 0.4650.535 1.2 post cured 16 hrs 40° C. (%) Rest benzaldehyde casting 0.0030.003 0.005 0.07 4 mm Post cured 16 hrs 40° C. (%)

The results clearly indicate that good and efficient curing, beingindicated by short geltimes and high Barcol hardness of the curedobject, combined with low amounts of residues can only be obtained whenthe resin composition both contains copper and amine.

1. Two-component composition comprising a first component and a secondcomponent, wherein the first component is a resin composition comprisingan unsaturated polyester resin or vinyl ester resin, a copper²⁺compound, at least one N-containing organic base selected from an aminecompound and/or an ammonium salt; wherein the amine compound has thefollowing formula:

and the ammonium salt has the following formula:R¹R²R³N⁺H whereby R¹, R² and R³each individually may represent hydrogen(H), C₁-C₂₀ alkyl, C₅-C₂₀ cycloalkyl or C₇-C₂₀ alkylaryl, that eachoptionally may contain one or more hetero-atoms and/or substituents anda ring may be present between R₁ and R₂, R₂ and R₃ and/or R₁ and R₃,which may contain heteroatoms, wherein copper is present in an amount ofat least 50 ppm relative to the primary resin system, wherein the resincomposition contains less than 0.01 mmol cobalt per kg primary resinsystem, and wherein the resin composition has an acid value in the rangeof from 0.001-300 mg KOH/g of resin composition, and wherein themolecular weight of the resin containing reactive unsaturations is inthe range of from 500 to 200,000 g/mole, and wherein the secondcomponent comprises a peroxide compound.
 2. The two-componentcomposition according to claim 1, wherein the copper compound is acopper carboxylate or a copper acetoacetate.
 3. The two-componentcomposition according to claim 1, wherein the copper is present in anamount of at least 100 ppm relative to the primary resin system.
 4. Thetwo-component composition according to claim 1, wherein R¹, R² and R³are hydrogen.
 5. The two-component composition according to claim 1,wherein R¹, R² and R³ each individually may represent a C₁-C₂₀ alkyl. 6.The two-component composition according to claim 1, wherein at least oneof R¹, R² and R³ is an alkyl-O—R⁴ group, whereby R⁴ is hydrogen, aC₁-C₂₀ alkyl group or a ring is present between R⁴ and at least one ofthe other R groups.
 7. The two-component composition according to claim6, wherein the-O—R⁴ group is in the R-position with respect to thenitrogen atom.
 8. The two-component composition according to claim 1,wherein the amount of the N-containing organic base is from 0.05 to 5%by weight, calculated on the total weight of the primary resin system.9. The two-component composition according to claim 1, wherein a molarratio between the copper and basic functionality of the base is from40:1 to 1:125.
 10. The two-component composition according to claim 1,wherein the resin composition further comprises a radical inhibitor. 11.Cured structural parts obtained by curing a two-component compositionaccording to claim
 1. 12. A process which comprises radically curing atwo-component composition according to claim 1 in the absence of cobalt.13. The process according to claim 12, wherein the peroxide compound isat least one selected from the group consisting of hydroperoxides,perethers and perketones.
 14. The process according to claim 13, whereinthe peroxide compound is methylethylketone peroxide.
 15. Thetwo-component composition according to claim 10, wherein the radicalinhibitor is at least one selected from the group consisting of phenoliccompounds, stable radicals, catechols and phenothiazines.